a dish-based semi-quantitative food frequency questionnaire for assessment of dietary intakes in epidemiologic studies in iran: design and development

background: earlier forms of food frequency questionnaire (ffq) used in iran have extensive lists of foods, traditional categories and food-based design, mostly with the interviewer-administered approach. the aim of the current paper is to describe the development of a dish-based, machine-readable, semi-quantitative food frequency questionnaire (dfq). methods: within the framework of the study on the epidemiology of psychological, alimentary health and nutrition project, we created a novel ffq using harvard ffq as a model. results: the following steps were taken to develop the questionnaire: construction of a list of commonly consumed iranian foods, definition of portion sizes, design of response options for consumption frequency of each food item and finally a pilot test of the preliminary dfq. from a comprehensive list of foods and mixed dishes, we included those that were nutrient-rich, consumed reasonably often or contributed to between-person variations. we focused on mixed dishes, rather than their ingredients, along with foods. to shorten the list, the related food items or mixed dishes were categorized together in one food group. these exclusions resulted in a list of 106 foods or dishes in the questionnaire. the portion sizes used in the ffq were obtained from our earlier studies that used dietary recalls and food records. the frequency response options for the food list varied from 6-9 choices from “never or less than once a month” to “12 or more times per day”. conclusions: the dfq could be a reasonable dietary assessment tool for future epidemiological studies in the country. validation studies are required to assess the validity and reliability of this newly developed questionnaire.